Scrolls are considered basic ninja tools, same as shuriken and kunai. I don't think you need to state that, as it's kinda logical. If your chakra is blocked then you can't use any ninjutsu, because it requires your chakra. Same goes for this. You need to channel your chakra into the scroll, in order to activate it and release the dragon.Do i have to announce at the beginning of a battle that i have these scrolls or it's irrelevant. Plus if for example i'm battling a hyuuga and i have my chakra blocked , can i still use these two jutsus??
are the jutsus guided? like if i send them, can it be evaded or it must be blocked
I believe it is guided, but to a certain point. You could make them come from an arc, I belive, but you couldn't just change their trajectory, avoid the opponents technique and continue towards him. Doing this would also put your at risk, because of the unhandled technique coming towards you.